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Discussion Starter · #1 ·
I just finished my 95" build and I've noticed after short rides that I'll have a few drips of oil coming out of the breather tubes. I never had this problem before. I'm running a Feuling oil pump and a Delkron camplate w/ a Zippers shim turned down to .150 on the oil relief valve spring. I've got an Arlen Ness oil pressure guage and I have 55 psi at cold start and 20 psi at hot idle. I also have 200 ccp in both cylinders. I'm running Amsoil 20-50 oil. Also a H-D super premium oil cooler. I'm currently using the plastic breathers but have the aluminum ones to put in when I change my tins. I'm sure the HG and rocker gaskets are in right. Any ideas? TIA. :dunno: :confused:
 

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Discussion Starter · #2 ·
Bumpin it up. Any ideas guys or is this posted in the wrong place? Thanks in advance.:dunno: :confused:
 

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Try using 1/4 to 1/3 qt less oil on oil changes and see if that helps. Increased displacement places more work load on the breathers --- more windage. It's easy to upset the pressure balance in these motors and even though the Feuling pump has better scavenge capability than stock it can still be affected. Also, sealing problems at the pump O-rings and at the cam plate to crankcase joints can contribute to carryover problems. I won't comment on Delkron cam plates other than to say there have been some issues with both sealing and dimensions ---YMMV.
The pump "alignment" that is purported to solve oil carryover is mostly a crock, more often the "re-alignment" just moves things enough to get an O-ring that had some leakage to seal up. The pump only needs to find it's natural center and that's what the alignment does. It can be done by turning the back wheel, using the starter (remote starter switch works great) to turn the motor, or using the alignment pins (need specials for the Feuling pump, some 1/4 -20 FHCS machine screws work just fine) as outlined in the SM.
The plastic breathers can warp and cause carryover problems, also the big O-ring between the rocker support plate and the rocker box can leak and cause problems as well.
 

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Discussion Starter · #5 ·
vtwin_nut said:
Try using 1/4 to 1/3 qt less oil on oil changes and see if that helps. Increased displacement places more work load on the breathers --- more windage. It's easy to upset the pressure balance in these motors and even though the Feuling pump has better scavenge capability than stock it can still be affected. Also, sealing problems at the pump O-rings and at the cam plate to crankcase joints can contribute to carryover problems. I won't comment on Delkron cam plates other than to say there have been some issues with both sealing and dimensions ---YMMV.
The pump "alignment" that is purported to solve oil carryover is mostly a crock, more often the "re-alignment" just moves things enough to get an O-ring that had some leakage to seal up. The pump only needs to find it's natural center and that's what the alignment does. It can be done by turning the back wheel, using the starter (remote starter switch works great) to turn the motor, or using the alignment pins (need specials for the Feuling pump, some 1/4 -20 FHCS machine screws work just fine) as outlined in the SM.
The plastic breathers can warp and cause carryover problems, also the big O-ring between the rocker support plate and the rocker box can leak and cause problems as well.
vtwin_nut - First, let me thank you for answering my thread!! I beleive when I first fired up the motor after the rebuild, that I had too much oil in it. I added an oil cooler and I filled it with a squirt bottle before I connected the final hose. Then I also filled the oil filter before I put it on. Then when I filled the oil tank I put a little over 3-1/2 qts in. All in all, after running it for a few minutes I checked the level and it was to the top of the mark. I had to let about half a qt. out. When I changed the oil after running it for about an hour. I put in just enough so when I check it cold it's about a third of the way up the mark. I could let about 1/4 of a quart out but I wouldn't feel comfy with more than that. As far as the Delkron camplate I had Vitron o-rings machined at all the camplate to crankcase joints as well as 'U' grooves cut at the oil feed holes. I'll try to post a pic so you can see what I meen. I did have to put a +1 pinion gear in to get w/in specs. The gear drive is very quiet so I don't think that is it.
I aligned the oil pump with alignment pins and by rotating the engine as I tightened it. I think that is OK.
I rebuilt the plastic breathers and put new o-rings in but when torquing the breather bolts I did notice the breathers starting to flex, so I never did get them to torque but did use loctite on the bolts so they shouldn't loosen. Which leads me to beleive it might be the breathers. I did go and get the aluminum ones and will install them when I take off the gas tank when I change my tins. I have built quite a few motors in my time but I'm relatively new to Twin Cams. I've never encountered this before and this motor never really had oil come out of the breathers before. Unless it stops when I change the breathers, I'm stumped. Again, thanks for the reply.:dunno:

P.S. - I can't get a picture of the camplate to load. If you send your email address to me at [email protected] I'll send you one in an email. Thanks - Kurt
 

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normal blowby?

just broke 1600 miles on 95 build and had to add almost a half quart of oil. have dougherty crankvents and that's where it's coming from. after a long run at 3200 rpm it leaves a nice film of oil on the right sidecover and right saddlebag
 

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Mine blows a little too. Maybe someday, I'll put in the metal breathers, but unless it gets bad, I'm disinclined to do mechanical work. I don't think things like krank vents and tiny air cleaners work well, and your experience with Doherty vents illustrates that. Seems to me the oil has to go somewherre - and it's going out. I just have my heads vented thru black hose down the back of the motor, along the frame and terminating at the far end of the swingarm. Works for me.
 

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I actually got mine to sump on Saturday... I run the Doherty air vents and that has helped, but running at 95+ for a few miles and backing off can cause some problems with sumping... I rather clean the saddlebag than the air filter...
 

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Discussion Starter · #9 ·
I rather clean the saddlebag than the air filter...
I'd rather figure out why it's doing this and figure out a way to fix it. I'm seriously thinking of going back to the stock oil pump and see what that does.:huh:
 

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RoadKingCurley said:
I'd rather figure out why it's doing this and figure out a way to fix it. I'm seriously thinking of going back to the stock oil pump and see what that does.:huh:
Try calling Steve at GMR. He fixed mine from doing it most of the time. I have the stock pump and it works fine. I only get sumping when running at 4800+ for several miles and back off to normal speeds. It's worth a call...
Good luck...
 

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Discussion Starter · #11 ·
rdking2005 said:
Try calling Steve at GMR. He fixed mine from doing it most of the time. I have the stock pump and it works fine. I only get sumping when running at 4800+ for several miles and back off to normal speeds. It's worth a call...
Good luck...
What exactly did he do?:dunno:
 

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check your PM...
 

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before you do that...

RoadKingCurley said:
I'd rather figure out why it's doing this and figure out a way to fix it. I'm seriously thinking of going back to the stock oil pump and see what that does.:huh:
I have the fueling and after the 95" build on my flstc it started to mist oil onto the bag and it would drip oil on the timing cover at stops -not a puker like some others though. It never did this as an 88".

One thing I also did after the build was changed my air cover to the round retro hd style right after the build. To make a long story short, at one point of troubleshooting the problem I left the hd cover off during a jet change and just left the k&n filter on and it has not misted or dripped oil in 7k miles. works for me...
 

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Discussion Starter · #16 ·
I could be totaly off base here but I'm thinking that with the extra oil pressure from the Feuling oil pump, that the rocker boxes are getting overloaded with oil and the breathers can't handle it. The umbrella's that I took out were green and seemed heavier than the new gray ones that came with the rebuild kit. Maybe that has something to do with it. Trouble with that is, the new aluminum breathers I've got have the same gray umbrellas. So is it gonna do the same thing with the aluminum breathers as it's doing with the plastic ones? If it still does it after I R&R them, I'm gonna install the stock oil pump back in it and see what that does. I didn't have an oil press. guage on when it was stock so I don't know what the pressure was. Right now I'm gonna take about a cup more oil out of the oil tank. Reducing the oil by a third of a quart seemed to slow it down some. With the scavanging capabilities of the Feuling a cup less oil shouldn't hurt anything, I hope!! :huh:
 

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RoadKingCurley said:
I could be totaly off base here but I'm thinking that with the extra oil pressure from the Feuling oil pump, that the rocker boxes are getting overloaded with oil and the breathers can't handle it. The umbrella's that I took out were green and seemed heavier than the new gray ones that came with the rebuild kit. Maybe that has something to do with it. Trouble with that is, the new aluminum breathers I've got have the same gray umbrellas. So is it gonna do the same thing with the aluminum breathers as it's doing with the plastic ones? If it still does it after I R&R them, I'm gonna install the stock oil pump back in it and see what that does. I didn't have an oil press. guage on when it was stock so I don't know what the pressure was. Right now I'm gonna take about a cup more oil out of the oil tank. Reducing the oil by a third of a quart seemed to slow it down some. With the scavanging capabilities of the Feuling a cup less oil shouldn't hurt anything, I hope!! :huh:
Not sure if the breathers are causing it, but running it with 1/2 qt less oil is one of the common recommendations to fix the blowby problem. When all else fails most will run the hose down to a breather and then a small collector that can be emptied out. My oil pressure is ~20 psi at hot idle and it usually runs ~50 psi at hiway speeds and no mist or pukes -doubt it is too much oil to the heads causing it.
 

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Before you go spending lots of money on replacment parts go to americanrider.com and check the article on blowback. It gets to the root cause of the problem which is the cam overlap. Make sense?
 

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Just to let you know I've got the aluminum breathers & I've had blow-by with the stock 88" & also the 95" build. I run my bike hard & have always been told speeps above 80 mph exacerbate the problem. I ran a puke tube from the breathers to the ground. I usually get a drop or two a day.
 

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Discussion Starter · #20 ·
ratrider said:
Before you go spending lots of money on replacment parts go to americanrider.com and check the article on blowback. It gets to the root cause of the problem which is the cam overlap. Make sense?
@gree: Ding, ding, ding!! Looks like we have a winner!! ratrider, looks like you hit the nail on the head. Everybody read the following;
V-Twin Tech Oil blow-back American Rider Sunday October 23, 2005 Email this article to a friend! </email.cfm?goto=/output.cfm?id=1021663> by Joe Minton



Q

I have a problem with my 2002 FLHRCI and was hoping that the staff at American Rider could shed some light. The dealer installed, at time of purchase, a Stage One upgrade with the high-flow intake breather kit with Screamin' Eagle exhaust. My problem is oil blow-back through the breather. Is this common and what, if anything, is the fix?

Al Mason

via email



A

Your problem is a mechanical one and there could be several causes. Oil from the engine breather and the oil from the filter element make the liquid that blows back oily. Note that all engines tend to do this, including completely stock ones. Normally the stock air filter assembly traps this blow-back which later finds its way back into the engine when the running rpm increases.

The basic problem is the engine is blowing back some of the air/fuel mixture it has drawn into its cylinders. This is because the intake valves are not closing soon enough to trap the mixture in the cylinders.

This blow-back or "reversion" problem is dependent on engine speed. For each cam design, with its particular intake valve closing event, there is an rpm above which the blow back stops. The sooner the valves close, crankshaft-degree wise, the lower the rpm at which the blow-back stops.

Most aftermarket cam designs aggravate this problem because they close the intake valves later than stock cams. The answer is to either run at a higher engine speeds or fit a set of cams that close the intake valves earlier.

Poorly designed or inappropriate exhaust systems can also increase the amount of blow back, sometimes enormously. The worst offenders are overly long, open straight pipes.

Try this: Ride at a speed and in a gear (fourth or fifth) at which the problem occurs. Note that you are getting blow-back. Now, maintain the road speed but shift into the next lower gear. If you went from, say, fourth gear at 50 mph to third gear at 50, the blow-back should stop or be greatly reduced. The reduction is due to the 25 percent or so increase in rpm which better matches the cam design.
I noticed yesterday that my bike runs smoother, when cruising around town, at a lower gear with more rpm. This is just an example, I used to cruise around in 4th gear at 2000-2500 rpm, I now cruise around in third gear at say 2400-2900 rpm. Same speed, lower gear, higher rpm. And no blow back!! I still haven't had the bike tuned yet and I don't know if that will change anything, but I feel better knowing what caused this. I am also installing a Baker DD6 tranny soon. Guess I'll have to learn how to ride it all over again!!:duh?:
 
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